Rotary tool lathe



Sept. 2, 1947.

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ROTARY TOOL LATI-IE Filed April l0, 1944 9 Sheets-Shea?l 9 E-/Z 30 j-/ THROW cem-sums or cEnNKHAF! MAIN BERE/N65 Loro Hofweor-L.

l Patented Sept. 2, 1947 ROTARY TOOL LATHE Lloyd Hornbostel, Beloit, Wis., assigner to Beloit Iron Works, Beloit, Wis., a corporation of 4 Wisconsin Application April 10, 1944, Serial No. 530,371

21 Claims.

l I `This invention relates to machine toolsand particularly to rotating lathes especially adapted `for finish cutting the pins, heels. and cheeks of crank shafts.

The invention will hereinafter be specifically described as embodied in a crank pin turning lathe which has stanchions for clamping the main bearings of a crank shaft to iixedly secure the crank shaft in position and which has one or more rotating tool carriages each movable around the fixed crank shaft to carry and guide a cutting tool for cutting each pin of the crank shaft to finished dimensions, for cutting the inside faces Aor cheeks of the webs between the pins and the main bearings of the crank shaft, and for cutting the heels of the Webs adjacent the main bearings. These operations cannot ybe satisfactorily carried out on a conventional work rotating lathe rbecause, in such lathes, it-is necessary that the crank shaft rotate about the center line of the pin being machined, and a lathe with an exceptionally large diameter swing is thus required. In addition, Since the crank shaft must be rotated off.center in a conventional lathe, a clumsy arrangement necessitating the use of counterweights and a special steady rest is required. This clumsy arrangement and added weight frequency necessitates slow cutting speed. Special fixtures must be used for special sized crank shafts, and a number of these fixtures would be an expensive item requiring added storage space if a number of different types of crankshafts are to be machined. A long setup time is required and, in addition, very accurate machining is impossible. The crank pin turning lathe of this invention, on the other hand, avoids all of the problems encountered With the turning of crank pins in conventional rotary work lathes by holding the crank shaft stationary and rotating the tools around the crank shaft. Machines of this invention are easily set up to accommodate crank shafts of widely varying size ranges, machine the crank pins in one-half to one-fourth the time heretofore required, and carry out the rapid machining at tolerances within .001 inch even on the largest size crank shafts.

It should be understood, however, that the principles of this invention are not limited for embodiment in the hereindescribed specific crank pin turning lathes, since they are applicable to other types of machine tools.

The crank pin turning lathes of this invention have an elongated bed providing a track for a carriage. The carriage, in turn, provides a track for a-main ring housing which is shiftable on the (c1. sia-9) 2 carriage transversely of the bed. 'The bed also provides tracks for crank shaft suppvrting stanchions and stands to securethe crank shaft in fixed relation through-the center of the ring housing. A main ring isrotatable inthe housing and carries one or more tool carriages which are slidable on gibs'or ways provided on a face of the main ring and feed screws move the carriages toward and away from the center of the ring. This structure permits the ring housing to be moved with the main carriage in axial directions on the bed of the machine for advancing the tool carriages and tools longitudinally of the ixedly held crank shaft. It also permits the main ring housing to move transversely of the bed of the machine on the main carriage to position the tools to travel about the proper centers desired for the turning operation. The depth of cut is controlled by movement of the tool carriages on the main ring.

A feature of the invention is the provision vof a readily removable main ring bearing which has thrust bearing relationship with the ring for the full 360 of rotation of the ring and which has radial bearing relationship with the ring along two spaced arcuate portions at the bottom of the housing. The ring is radially spaced from the bearing at all points except atthe two spaced arcuate portions of the bearing.

A further feature of the invention is the maintenance of an oil seal between the main bearing and the ring which it supports by utilizing the thrust faces of the bearing to confine the oil.

A still further feature of the invention deals with the feeding of lubricant to the main bear-y ing. According tothe invention` lubricant is fed into a wedge-like gap and is actually Ldrawn onto theradial bearing surfaces by the rotating ring.

A still further feature of the invention is the provision of adjustable thrust clearance devices for the main bearing. y,

Still another feature of the invention is the provision of voil seals and oil groot/res inthe bearing housing which, due to normal rotation of the main ring, fling oil away fr'om the opening between the main ring and housing, thereby effectively returning the oil to the interior of the housing and preventing leakage.

Another feature of the invention is the provision of non-clogging carriage supports for the tool carriages.

It is, then, an object of the invention to provide a machine tool having a tool-carryingr ring receiving the work therethrough and mounted for rotation as Wellas movement in longitudinal and transverse directions for accurately guiding and driving cutting tools so as to maintain tolerances as low as .001 inch.

Another object of the invention is to provide a crank pin turning lathe. of improved design for maintaining accuracie's` in the ilnishing of crank shaft pins, cheeks and heels which have not heretofore been achieved.

A further object of the invention is to provide an improved bearing'construction for the main ring of a. crank pin turning lathe.

Another object of the invention is to provide an improved lubricating `system for the main bearing of a crank pin turning lathe.

Still another object of the invention is to provide tracks or ways for tool carriages on the main ring of a crank pin turning lathe which are self-cleaning and cannot become clogged by chips cr turning.

Other objects and features of the invention will become apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of preferred exampleonly, illustrate one specific embodiment of the invention.

n the drawings:

Figure 1 is a perspective view ofa crank pin turning lathe according to this invention.

Figure 2 is a front end elevational view of the ring and ring housing of the lathe shown in Figure 1.

Figure 3 is an enlarged radial cross-sectional view, with parts omitted. taken along the line III- III of Figure 2.

Figure 4 is an enlarged/radial cross-sectional v view, with parts omitted, IV-IV of Figure 2.

Y Figure 4-A is a fragmentary cross-sectional view taken along the line IV-A-IV-A of Figure 4.

Figure 5 is a rear end elevational view of the main ring, showing the hub of. the ring in vertical cross section and taken along the line V-V of Figure 3.

Figure 6 vis a front elevational view of the ring housing with the ring removed but showing the ring hub in vertical cross section and taken along the line VI`VI of Figure 4.

Figure 'l is a fragmentary enlarged front end elevational view of the main ring and one of the tool carriages on the main ring.

Figure 8 is across-sectional view, with parts in end elevation, taken along the line VIII-VIII of Figure 7. i

Figure 9 is a vertical cross-sectional view, with parts in end elevation, taken along the line IX-IX of Figure '7.

Figure 10 is a longitudinal cross-sectional view. with parts-in side elevation, taken along the line X-X of Figure B.

Figure 11 is an end elevational view of the pin and strip of Figure l0.

Figure 12 is an enlarged vertical cross-sectional view, with parts in elevation, taken along the line XII- XII of Figure 7.

Figure 13 is an isometric view of a wedge block shown in Figures 'I and 12.Y t

Figure 14 is a piping diagram of the lubricating system for the main bearing and gear box.

Figure 15 is a somewhat diagrammatic view of the drive for the main ring and one of the tool carriages.

Figure 16 is a side elevational view of a forging from which a crank shaft is made.

Figure 17 is an end elevational view of Figure 16,` i

taken along the line Figure 18 is a side elevational view illustrating the first cutting operation on the forging of Figure 16, to produce a crank shaft.

Figure 19 is an end elevational view of Figure 18.

Figure 20 is a side elevational view illustrating the second operation on the forging of Figure 16, to produce a crank shaft and showing the main bearings of the shaft turned down to finished diameter.

Figure 21 is an end elevational view of Figure Figure 22 is a side elevational view of an unfinished crank shaft after the lathe-turned forging of Figure 20 has been twisted.

Figure 23' is an end elevational view of Figure 22.

Figure 24 is a fragmentary side elevational view of a portion oi' a finished crank shaft made from the forgings of Figures 22 and 23 and bearing legends identifying the various parts of the crank shaft including the parts that are finished by the crank pin turning lathe of this invention.

Figure 25 is a transverse cross-sectional view. taken along the line XXV- XXV of Figure 24.

As shown on the drawings:

The machine in general As shown in Figure 1, the crank pin turning lathe Il of this invention includes an elongated bed ii providing longitudinal tracks on which are slidably mounted a main carriage l2, crank shaft supporting stanehions i3, i3, and crank shaft supporting stands such as il. A crank shaft i5 has main bearings 16a clamped by the stanehions i3 to support the crank shaft in fixed relation above the bed |l.`

A main housing I6 is slidably mounted on the main carriage i2 for transverse movement across the bed i I. The main housing Il is thus movable longitudinally and transversely relative to the bed Il.

As shown in Figures 1 and 2, the main housing Il has a. central vertical ring portion Ila with laterally projecting portions lib andv llc; The portion |81: has a box i1 provided on the end thereof while the portion IBc has a box il on the end-thereof. The boxes l1 and i8 house operating parts for the machine with the box I8 containing gear drives and controls, and the box Il containing lubricating mechanism.

As shown in Figure 1, the stanchionfll on the front of the machine carries a platform Pr and a stairway Si depends from the rear side of the platform P1. The main housing IB has a platform P2 secured to the box i8 at the front side of the machine and stairways S: and Sa depend from opposite ends of this platform. A platform P3 bridges the platforms Pi and P2.

A main ring I9 is rotatably mounted in the ring housing |6a and receives the crank shaft i5 through the central aperture [9a thereof.

As best shown in Figure 2, the front end face of the main ring I9 carries parallel ways 20-20 on diametrically opposed sides thereof together with tracks 2| spaced from the ways. Tool carriages 22 are slidably mounted on the ways and tracks 20 and 2l and are fed toward and away from the center of the aperture 19a by means of feed screws 23 driven by drive gears encased in housings 24.

The gear box i8 carries a motor M which drives the main ring i9 in the ring housing I6 and also drives the feed screws 23. Gear shift levers y L are provided on the box i8 for changing speed Work done by the machine As shown in Figures 16 and 1'7, an elongatedI metal forging or billet 30 is substantially rectangular in cross section and has reduced substantially square ends 30a. This billet 30 ls the starting piece from which the crank shaft I is made. As indicated in Figures 18 and 19, the forging 30 has pairs of transverse cuts 3| along -the length thereof at properly spaced intervals,

and pieces of metal between the pairs of cuts 3i are separated from the body by torch cutting, sawing or the like, along the lines 32. The resulting blank has axially spaced segments on opposite sides of the center line thereof as shown. This blank is then placed in a rotating work lathe or conventional engine lathe and main bearings a for 'the crank shaft I5 are latheturned as shown in Figure to provide a crank shaft blank having4 webs lib all extending in one direction from the main bearings lia and carrying at theirv outer ends crank pin-forming portions |50, The outer ends of these projecting portions i5b can be rounded as at lid by rotating the work lathe since the blank is rotated about the center of the main bearings Iba and the portions ld can be readily cut by a stationary tool. In addition, the outside faces 15e of the webs lib can be cut by the rotating work lathe. The crank pins I5c,'the inside cheeks l5f, and the heels IBg cannot be out by a conventional lathe without great diiiiculty because the work must be rotated off center for the formation of these portions.

Therefore the blank of Figures 20 and 21 is next twisted as shown in Figures 22 and 23 to position the crank pin-forming portions llc at the desiredI angular relationship around the main bearings 15a. This provides the crank shaft blank which is acted upon by the machine I0 of this invention. As shown in Figures 1, 24 and 25, the crankshaft I5 has the pins I5c thereof, the cheeks I5f thereof, and the heels 15g thereof finish formed to tolerances never heretofore obtainable. The throw of the crank shaft is illustrated in Figure 24 together with the center line of the crank shaft and the center line of rotation of the main ring I9 of the machine.

Crank shafts have the cheeks, heels, and pins thereof finished to tolerances of even less than .001 inch in one-half to one-fourth the time heretofore required by the machine i0 of this invention, and crank shafts of tremendous size can be accommodated since they are held stationary during the pin-turning, cheek-forming, and heelcutting operations. Tremendously large crank shafts for marine engines and stationary engines can be accommodated. Crank shafts sixty to eighty feet long and having pins two to three feet in diameter can be handled with ease.

The main ring bearing As best shown in Figures 3 and 6, the ring housing I6a has an open front face bounded by a downturned lip 30 together with a closed back wall 3i having an inwardly offset portion Madeflning a central operture 32. An annular chamber 33 is thus provided as shown in Figures 3 and 4, and the bottom of this chamber communicates through a port 34 with a sump defining base 35.

A bearing ring 38 is bolted to the inwardly offset portion 31a of the back wall 3I` by means of screws 31 passed through the back wall portion 3Ia and threaded into the ring. The bearing ring 36 projects radially inward from the wall defining the aperture 32 of the housing and has an inner annular peripheral wall 36a, a back end face 36h,

`and a front end face 36c. `The inner peripheral wall 36a is not perfectly circular. but is formed by first cutting a straight circular cylindrical bore in the ring 33 and by then shifting the center of cutting tocut anew bore into the top portion of the old bore, thereby relieving the top of the old bore.

The main ring I3, with the aperture Na therethrough, has a hub 31 around the aperture 13a. This hub 31 has a straight circular cylindrical peripheral portion 31a.-

As shown in Figures 3, 4 and 6, the hub 31 of the main ring I3 fits into the bearing 33 and the periphery 31a thereof is spaced from the bearing wall 36a around the top half of. the bearing but is supported on the bearing wall 36a around the bottom portion of the bearing.

The main ring i3 has an annular finished wall portion 38 extending from the front end of the hub 31 thereof for thrusting on the wall 38e of the bearing as shown in Figures '3 and 4.

A ring member '33 fits` around a pilot portion 31h of the hub 31 and is secured vto thehub by.

means of bolts 40. This ring 39 has a at inner face 33a thrusting against the face 33h of the bearing.A

Shims 4i are provided between the ring 33 40 \and a shoulder 31o at the inner end of the pilot portion 31h for controlling the distance between the faces 38 and 33a and thereby controlling the thrust bearing relationship against the faces 36h and 38o of the bearing ring 33. The bearing 36 has a cylindrical outer periphery 33d extending therearound and a pair of arcuate shoes 42 are disposedv around the bottom part of the bearing wall periphery 36d in spaced opposed relation as shown in Figure 6. These shoes 42 are slidably mounted on a pilot portion 3Ib of the back wallA 31a as shown in Figure 4 and have tapered outer peripheries 42a. Bolts 43 extending through the wall portion 3io. are threaded into the shoes 42 to secure them to the wall 3Ia. As shown in Figure 4-A, bolts 44 are also threaded through the wall portion 31a adjacent the bolts 43 and have inner end portions for acting on the end wall of the shoe 42 to control the setting of the shoe. Thus the bolts 44 act as position-Setters for the shoes while the bolts 43 secure the shoes against the bolts 44 on the wall 31a. y

The main ring I9 has a tapered wall 45 in .spaced concentric relation around the hub 31 thereof coacting with the taperedwalls 42a of the shoes 42 to hold the hub periphery 31a of the ring I3 on the radial bearing wall 36a. of the bearing ring 36. The shoes 42 are accurately ad/ the bearing wal1'36a is cut away to provide av pocket 46. Therefore, only two arcuate segments,

designated at A and B respectively in Figure 14, extend from the ends of the pocket 46 around the lower portion of the hub wall 31a. The bearing segments A and B are preferably arcs of about 70. i

Asshown in Figure 6, the shoes 42 are commensurate in length with the lengths of the arcs A and B.

From the above descriptions it will be understood that the main ring I9 is supported by a combined thrust and radial bearing ring 36. The bearing ring 36 providesA two spaced arcuate radial bearings around the bottom half portion of the main ring and proper bearing relationship between the main ring;and these bearing segments is maintained by the shoes 42 which are accurately shifted to take up clearance by means of adjusting screws 44 and locking screws 43.

Proper radial bearing relationship is maintained between,y the side walls 36h and 36e of the bearing ring 36 'by adjusting a. ring 38 on the main ring I8.

The main bearing ring I4 is readily removable from the housing I6a through the open front face of the housing.

The drive for the main ring and the tool carriages ner face thereof near the outer periphery by means of bolts I. This ring gear 50 is disposed in the chamber 33 provided by the housing I6a.

The main ring I8 has'a cylindrical wall or pilot portion 62 therearound inwardly of the ring gear 56 and outwardlyfrom the tapered wall 45 thereof. k A second ring gear 53 is rotatably mounted on this pilot portion 52v and held thereon by means of plates 54 bolted at spaced intervals to the inner face of the main ring I8. 'Ihe ring gear 53 has a double row of teeth 53a and 53h therearound.

As shown in Figure l5, the motor M drives a pinion 55 which, in turn, drives a gear 56 for rotating a shaft 51. The shaft 51 drives a pinion 58 rotating a gear 58 on a second shaft 66 and this shaft 68 has a main drive gearll meshing with the main ring gear 58 to rotate the main ring I9.

A second gear 62 keyed on the shaft 60 drives a gear 63 of a differential unit 54.

The gear 63 is freely mounted on bearings 65 around the differential shaft 66 and has bevel f gear teeth 61 around the hub thereof meshed with spur gears 68 on a spider 68 keyed to the differential shaft 66.

A second gear 10 is freely rotatable around the differential shaft 66 on bearings 1I and has bevel teeth -12 on the hub thereof also meshing with the spur gears 68. This second gear 1I)v engages the row of teeth 53a of the ring gear 53. A gear 13 is keyed on the shaft 66 and this gear is connected to change-speed transmission mechanism and reversing feed clutch mechanism so as to drive the shaft 66 in a direction and at a speed predetermined by setting of the transmission and clutch. Whenever the shaft 66 has relative movement to the gear 63, the diierential unit 64 will be operated to actuate the gear 18 and drive the ring gear 53 around its pilot support 52. The row of teeth 53h on the ring gear 53 mesh with spur gears 15 keyed to shafts 16 projecting through the front face of the ring I9 into the housings 24. Worms 11 are'provided on the shafts 7B meshing with worm wheels 18 on the feed screws 23 for the carriages 22.

From the above descriptions it should be understood that the motor Mdrives the ring gear 58 for rotating the main ring I8, and also drives a gear 63 of a diierential assembly 64 including a differential shaft 66 having a gear A13 keyed thereon for causing rotation of a gear 16 driving the sliding ring gear 53. The gear 63 is connected through a speed changer and reversible clutch system of gears back to the gear 13 so that the ring gear 53 is driven only when the gear 13 rotates at a different rate or in a different direction from the gear 63. The single motor thus drives the main ring I8 about its own axis, and drives the feed screws to actuate the tool carriages in radially inward and outward directions.

The main ring lubrication system As shown in Figures 2, 4, 6 and 14, the oil sump 35 provided beneath the housing chamber 33 receives lubricant through the port 34 and thus provides va lubricant reservoir, from which oil is drawn through a pipe into a pump 8| and pumped thereby through a pipe 82 into and through a filter 83 through a pipe line 84 connected with pipes 85 and 86. As shown in Figure 2, the pump and filter are located in the box portion I1 of the main housing I6.

The pipe line 85 extends upwardly through the box I1 and thence into the chamber of the ring housing I6a where it is connected to an arcuate pipe 81 surrounding the bearing 36 in the space between the outer periphery of this bearing and the tapered wall 45 of the main ring I8. A sump 88 is formed on the inner face 36a of the bearing 36 at the point where the hub 31 of the main ring comes in contact with the bearing wall 36a on the descending side of the hub. This sump thus communicates with a closing wedge between the walls 36a and 31a.

As explained hereinabove, a relieved portion 46 is providedl at the bottom of the bearing 36 so that the hub wall 31a of the main ring rides on two arcuate segments A and B. A sump 89 is provided in this cutaway portion 46 immediately adjacent the bottom of the bearing segment A.

A pipe 90 connects one end of the pipe 81 with the sump 88 while a second pipe 9i connects the other end of the pipe 81 with the sump 89. The pump 83 supplies oil to the sumps 88 and 89 at pressures determined by a reducing valve 92 in a pipe line 93 between the pipe 86 and the feed pipe 80. The sump 88 supplies the oil into the closing wedge at the top of the bearing segment B while the sump 88 supplies oil into the bottom of the bearing segment A. Since the main ring I9 only rotates in a clockwise direction oil will actually be drawn out of the sumps by converging wedge action between the bearing surfaces 36a and 31a to form a film of oil between the bearing segments A and B and the bearing 31a.

The pipe 86 extends across the bottom of the housing I6 above the sump 35 into the box I8 where it supplies lubricant to gears (not shown) in this box. A branch pipe 86a (Figure 2) is provided on the pipe 86 in the chamber 33 of the ring housing I6a to discharge lubricant onto the gear 6I meshed with the main ring 58.

As shown in Figures 3 and 4, oil from the sumps 88 and 89 lubricates the bearing walls 36a and 31a and, being under pressure, will also flow between the thrust bearing walls 36h and 39a, and 36e and 38. Any oil which Works past the thrust bearing walls 36h and 39a drains either into a 9 trough 95 provided in the ring 36, or a trough 93 provided in the back wall 3|a of the ring housing ia around the aperture 32 in this ring housing. The oil thus flows away from the gap between the ring member 39 and the wall defining the aperture 32. The oil drains around the rings in the troughs 95 and 96 to the bottom half of the ring where it drops by gravity into the chamber 33 and through the port 34 into the sump 35. Centrifugal action tending to throw the oil upwardly causes the oil to be trapped in the grooves away from the gap between the ring member and wall of the aperture 32. To further seal this gap, the ring member and wall can be provided with a series of grooves 91 acting as traps for the oil.

A plate 90 is carried by the ring member 30 to overlap the back wall 3|a of the housing and to ride on a seal ring 99 carried in this back wall for sealing the gap.

The lip member 30V of the housing also has a trough formed therearound to drain oil to the bottomof the chamber 33. The gap |0| between the lip 30 and the ring I9 communicates with a series of annular grooves |02 in the lip and one carriage and its supporting and actuating structure need be described.

As shown in Figures '1, 8 and 12, the way 20 has vintegral pads or pontoons ||0 projecting from the rear face thereof. These pontoons or pads are in spaced opposed relation along the length of the way and ilt against the front face of the ring I9. They have rounded inner ends I Ia converging to points. As best shown in Figure 8, the lpontoons hold the way 20 in spaced relation outwardly from the front face of the ring I9 and `any cutting chips or turnings can readily fallthrough this space and will not rest on the lrounded inner ends ||0a of the pontoons.

Bolts I|| extending through the pontoons I|0 4arethreaded into the ring I9 for securing the way in positionLand these bolts haveV heads IIIa :seated inl countesunk portions ||2 of the way so as lto be beneath theface of the way. l

The iacehoi .the'way has a slot I|3 along th length 'thereofwithundercut side walls |I3a and a cover plate ||4`fits in this slot and has outring to form traps for any oil entering thegap. j

A plate |03 is secured on the ring I9 to projectover the front face of the housing and rub on a seal ring |04. Seal rings 99 and |04 can be composed of felt or the like sealing material.

Any oil discharged from the gear B0 can be collected in 9, groove |05 provided adjacent the gear, and this groove diverges away from the gap III so that oil will be thrown inwardly away from the inner end of the gap |0I.

, From the above descriptions it will b e understood that oil is pumped from a sump in the bottom of the ring housing to the gear box and to the main ring bearing, where it communicates with' the main ring for being drawn by wedge action out of sumps to lubricate both the radial bearing and the thrust bearing of the main bearing ring. Oil flowing past the bearing surfaces sov ^ of the. way is'wider ,than the face thereof adand the gears is collected in annular troughs provided in the b earing ring and around the aperture in the rear face of the ring housing and the lip on the front face of the ringvhousing to flow around these troughs to the bottom of the housing and back to the oil reservoir in a sump at the bottom of the housing. Seals between the rotatrinlgfhousing are provided and the contour of the ringand housing adjacent the seals is such as to throw the oil away from the gaps between the ro- In order to maintain accuracy in the lathe-cutting operation of the machine, it is not only necessary that the main rotating ring I9 be rotated about an exact center point, but it is also necessary that the tool carriages on this main ring be accurately mounted for true radial feed movement.

Accurate mounting of the tool carriages 22,Y 2'2 is obtained according to this invention by utilizing L-shaped carriages and mounting the base leg of the L throughout its entire length on the way or gib secured on but spaced from the front face of the main ring, and by mounting the head end of the main leg of the L on a guide track in straddling relationship therewith.

The carriages 22, 22 and their supporting and actuating structures are identical, so that only ing ring part and the front and rear walls of the wardly tapered side walls dovetailing with the side walls H31;v so that the plate is secured in position. The'fplate' II'4 asian outer face ilush 'with th'f'oterface of the way, and the screw heads IIIa are thus covered and no recesses or otherrch-ip-retaining receptacles are provided.

sbjgst: show njin Figures 8 and 12, the Way 20 has taperedrsidewallsl-Iii so that the outer face jacent the'rihgll 'I'he base leg 22a of the carriage 22 has a dove-tailed groove IIB along the length thereof receiving the way 20. This groove IIB has side walls III parallel with the walls IIB of the way but spaced from these side walls. The groove I0 likewise has a base or inner wall spaced from the iront face and cover plate ||4 of the way. A wear plate IIB is bolted to the bottom face of the groove but terminates short of the end walls I|1. Screws ||9 are threaded into the leg 22a and have the heads thereof seated ush with the exposed face of' the wear plate IIS.

A bushing or liner strip |20 is positioned between that cnd wall I I! of the way 20 andthe adjacent wali III of the carriage nearest to the aperturey IIa of the ring. In other words the strip |20 is disposed between the way 20 and carriage legl on the radially inward end wall of the way. This strip |20 extends for the full length of the carriage leg 22a and has an upstanding' ilange I20a extending between the Aplug |22 has a fiat tapered top face122a engaging the bushing strip |20. The plug has an internally threaded longitudinal bore |22b receiving in threaded relation therein a screw |23 extending through the base leg 22a. As shown in Figure 12, the screw |23 acts as a means for drawing" the plug |22 further intothe'well |2I so that the level of the bushing strip |20 can be accurately' controlled and the exact position of lilac carriage maintained with respect to the way The raidally outer. end wall H5 of the way 20 receives a pair of bushing strips `|24 thereon projecting inwardly from opposite ends of the carriage leg 22a and having flanges |'24a depending into the space between the outer face of the way and the bottom of the groove ||3 in the carriage leg. The strips |24 have their innerends in spaced opposedrelation as shown in dotted lines in Figure '1. As shown in Figure 10, the `outer end portion of each strip is recessed as at |24b down to a shoulder |24c with anupstand ing rib |24d in spaced relation from the shoulder |24c. The strip has a top wall |24e riding on the Wall ||1 of the carriage leg 22a but this top wall |24e is tapered from the shoulder |24c to the inner endof the strip. Y

The end portions of the leg 22a of the carriage have stepped recesses |251 therein. The stepped recesses |25 are cylindrical but communicate with the strips |24.

The legs 22a are provided with internally threaded bores |26 atV the inner ends of the recesses |25.

A pin |21 is seated in each recess and .has a Vthreadediexid portion |21a-in screw thread rela- `ernbly. A locking screw |23 is threaded through the carriage to act on Athe pin forl holding the :same in adjusted position.`

,jThe carriage leg 22a has a straight cylindrical @bore |30 therethrough inwardly from the groove ||'|i for freely receiving the feedV screw 23 therelin as shown in'4 Figure '1. 'I hey bore |30 is materially larger than the threaded end 23a of the feed screw 23 and,.to seal' the bore against ingress of dirt, an end cap 13| can be bolted on the end face of the carriageslidably receiving `the feed screw 23therethrough. The other end of the bore can be closed by means of a plug |32. as shown in Figure 7.

The carriage leg 22g has a rectangular opening |33 cut therethrough transversely of the bore |30 and receiving `a nut |34 therethrough with the threaded aperture of the' nut in threaded engagement with the portion 23a of the -feed screw in the bore. A setrscrew |35 is threaded into the carriage for locking the nut |34 in the yslot |33. The slot or opening |33 slidably receives the nut |34 but holds the same against end movement and, being` of rectangular cross section, also holds thenut` against rotation.

The transmission housing 24, containing the worm and worm wheel 11 and 18- shown in Figure 15, also contains an overload clutch that will prevent damage to feed screw 23 'in the event that the carriage is subjected to overload. A

wooden dowel pin |36 projects from the housing 24 to receive the end face of the carriage leg 22a thereagainst in the event that' the carriage is moved too far toward the housing 24 and continued driving of. the assembly will only result in a slippage of the ,overload clutch so that the screw 23 will cease to rotate. In addition a block |31 can be mounted'on the outer end of the oarriage leg 22a as shown in Figure '1 to receive a second Wooden pin |38 thereagainst carried by a block |39 on the ring I3. The block |31 will l2 strike against the pin |33 in the event that the carriage is moved to the end of its radially outward stroke and continual driving will only result in the slippage oi the overload clutch. The pins |36 and |38 can be made of wood and are replaceable. v 1

The carriage 22 has the main leg 22h carrying the tool onwhich the tool jaws V2f are formed and the end of this leg is bifurcated to straddle the track 2| As shown in Figure 9, the track 2| is bolted to the ring |9 by means of bolts |40 and has an integral opstanding portion 2|a spaced outwardly from theface of the ring I9. The bifurcatedend of the carriage leg 22h has arms |4| with reduced end portions |4|a straddling the track portion 2|a and providing opposed faces |42 riding on the inner and outer side walls of the track portion 2|a.

In order to maintain these walls |42 in proper riding relation on the track portion 2|a, clamping bolts |43` extend through the legs |4| in threaded relationwith one of thelegs to draw the legs together. Alongside of each clamping bolt |43 there is provided a set screw |44 for maintenance of a desired spread condition for the legs. To properly adjust the surfaces |42 on the track 2|a, the screws |44 are set to maintain the legs in properly spaced apart relation and the screws `|43 are then tightened tor draw the rear leg against the end of the set screw |44.

From the above descriptions it will be understood that eachv tool carriage 22 has a base leg 22a and a main 1eg.22b. The base leg has a groove extending along the length thereof receiving a way or track therein. The end of the main leg is bifurcatedV and the bifurcated fingers thereof ride on a second track. The way and the second track are carried by the rotatable main ring of the machine. Since the tool carriage must be accurately carried on the main ring, and cannot have a loose t relationship therewith, a iirst bushing strip |23 is provided to adjust the exact level of the carriage on the way. A plurality of adjusting vplugs |22 are provided for this purpose and these plugs can be set so as toV maintain proper parallel relationship between the feedl screw for the carriage and the carriage-structure. Opposed bushing strips |24 are also provided with take-up means so as to maintain a tight sliding. at of the carriage on the way.

y The way is mounted on pontoons or pads which space it from the face of the main ring so that any chips or turnings released from the work by the tool cannot interfere with the free movement of the carriage. The track 2| need not be mounted on pontoons or pads, since chips or turnings do not fall on it because it is out of the path of falling chips or'turnings.

Summary The crank pin turning lathe of this invention,

as will be understood from the* above descriptions, includes an upstanding main rotating ring receiving the Work therethrough. This ring is rotatable vin a. housing which is movable in axial and transverse directions relative to the work. A bearing separate from the ring housing provides a one-piece radialand thrust bearing capable of holding lubricating oil pressure. The thrust bearings extend for a full 360 around the main ring, while radial bearings are spaced segmental cylindrical arcs of about on the bot- :Lubricant is fed into wedge-like gapsvbetweenthe main ring and the radial bearings, and is actually drawn onto the bearing surfaces by centrifugal force incident with rotation of the ring. The rotating ring and adjacent housing structure have cooperating oil seals..and lubricant;

troughs to return lubricant for recirculation. The same lubricant used for lubricating the radial bearings also lubricates the, thrust bearings. Proper thrust bearing clearance is maintained by gaskets or shims readily inserted or replaced between a ring member and the main ring to which the ring member is bolted.

The tool carriages are slidably mounted on jibs or ways and these jibs or ways are carried in spaced relation from the front face of the rotating ring on pontoons which vprovide spaces for chips to fall through. All bolt holes and other recesses capable o! collecting chips are sealed or covered. Very accurate adjustments are provided between the slide andthe carriage so that close tolerances can be maintained by the machine. Y

The machine is especially useful for cutting to very accurate tolerances the '1 crank pins,

`cheeks, and heels of crankshaftsyand since the crankshafts are statlonarily mounted in the machine, very large size shafts can be acted on without danger of deflection. e

It will, of course, be understood that various details of construction may be varied through a wide range" without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitatedby the scope of the appended claims.

I claim as my invention:

1. In a machine tool with a. bed having el n-l gated tracks thereon, a carriage mounted on said tracks for movement along the lengthl of the bed, an upstanding ring housing slldably `mounted on said carriage for movement transversely across the bed, and worksupports slid` ably mounted on said bed on opposite sides of said ring housing, the improvements of a main ring rotatably mounted in said ring housing and having Va hub adapted to receive therethrough work carried by said supports, opposed tool carriages slidably mounted on a face of the main ring, a feed screw for each tool carriage,`a main ring gear secured-on said main ring in said ring housing, a motor driving said main ring gear, a second ring gear rotatably mounted on said main ring in said ring housing, means driven by said second ring gear for driving said feed screw, and a differential mechanism rdriven by said motor to drive the second ring gear on said mainl ring.

2. In a lathe adapted for ilnish cutting the crank pins, heels and cheeks of crank shafts which includes a main bed having longitudinal tracks along the length thereof, a carriage slidably mounted on said tracks, a main .ring housing slidably mounted on said carriage for movement transversely of th'e bed, and crank shaft supporting stanchions on said bed on opposite sides of said housing, the improvements of a main ring rotatably mounted in said housing having an aperture therethrough for surrounding a crank shaft carried by said stanchions, a slide on a face of said main ring,.a track on said face of the main ring in spaced relation therefrom, an L-shaped tool carriagehaving a slot along the base leg thereof riding on said slide and a bifurcated end on the main lleg thereof riding on said track, a device controlling the position of said tool carriage on said slide, anopposed device controlling the clearance between .said tool carriage andk said slide, a feed .screw `for shifting said tool carriage radially of said main ring on said slide and track, a first ring gear in vsaid housing rotatably mounted on .said main ring driving said feed screwla second ring gear secured in said housing secured to said main ring, a motor carried by said housing, a gear train between said motor and said second ring gear, a differential mechanism driven by said -gear train for driving said rotatably mounted ring gear, said diierential mechanism adapted to operate for rotating the rotatable ring gear when the main ring is rotating to drive the feed screw, and a removable bearing ring in `said ring housing providing a radial hearing and a thrust bearing for said main ring.

3. In a machine tool, a. housing having a centrally apertured wall and an open face, a main bearing ring removably secured in said housing to said apertured wall and Vprojecting into said aperture, said main bearing ring having an inner peripheral wall and side walls at the end of the peripheral wall, a main ring having a hub projecting into said bearing ring and supported thereon on the inner periphery thereof, said main ring having an-end face for coacting with oneend wall of the main bearing, a ring member secured on the hubof the main ring having an end face thrusting against the other end face of they main bearingvring, and adjustable means Vfor shifting said ring memberon said hub of the vmain ring to control the thrust bearing clearance relationshipbetween themain ring and the bearing ring.

4. In a rotary tool lathe o f the type including a ring housingand a `rotatable tool carriagecarrying main lathe ring ,t he `improvements of a one-piece bearing ring member in said housing having opposed circular vcylindrical V segments forming radial bearings forfsaid main ring together with annular opposed' side faces providing thrust bearings for said main ring, and

an adjustable thrust ring on said main ring co- Operating with one of the faces of the main `nearing ring to regulatefthe thrust bearing clearance relationship between-the bearing ring and main ring.

5. In a rotary toolI lathe a ring housing having a yperipheral wall, a centrally apertured baci: Wall, and an open lfront face, a bearing ring in said housing, bolts connecting said bearing ring to Ysaid back wall of the housing around the central aperture thereof, said bearing ring having an inner peripheralwall and opposed side wallsin said housing projecting radially inward from the aperture-defining wall, a main lathe ring forming a front face for said open `front of the housing and having a hub projecting into the housing through said bearing ring, an adjustable ring-member on said'hub fitting said aperture of the housing in close-running clearance relationship therewith and providing a wall riding on a side wall ofxthe bearing ring, seal members in .sliding face torace relationship. rea spectively carried by said-back wall of the housing and by saidadjustable ring,v said lathe ring having a face adjacent said hub acting n the other thrust `face o f the bearing ring, means for introducing lubricant between the hub and the inner periphery of the bearing ring, and oil troughs in the bearing rinl and in the back wall of the housing for draining oil away from said cooperating seal members. f

6. vIn a rotary tool lathe an upstanding bearing ring, an upstanding lathe ring having a hub projecting into said bearing ring. the inner periphery of said vbearing ring being spaced from said hub around the topy thereof and at the central bottom portion thereof whereby said hub rides only on two localized arcuate sections of the inner peripheryof the bearing ring, a pocket cut into the inner periphery of the bearing ring immediately in advance of one arcuate segment on the descending side of the hub, a second pocket cut into the inner periphery of the bearing ring in the bottom thereof immediately in advance of the second bearing segment, vsaid pocket taper- Ving linto communication with the bearing segment, and means for pumping oil into said pocket to be drawn therefrom by the wedge-like action of the main ring hub asv it rides onto the supporting bearing segment.`

7. In arotary tool lathe a bearing ring having `an inner periphery and dat side walls at both terminal ends of the inner periphery, a lathe ring having a hub projecting through the inner periphery of the bearing and supported on said inner periphery, said main ring having a face at the inner end of the hub cooperating with one end face of the'bearing ring, a thrust ring slidably mounted on said hub having a face cooperating with the opposed end face of the bearing, "means for adjusting said thrust ring on said hub to maintain proper` operating clearance relationshipwith said main ring, and means for forc- 4ing lubricant onto the inner peripheryr of said 'bearing to flow under pressure over said thrust faces tosimultaneously lubricate the faces.

8. In a rotary tool lathe a main ring adapted for lrotating around the work, a slideway on a face of the main ring, an L-shaped tool carriage having a base leg-with a groove along the length thereof receiving said slideway anclv rideable thereon, said slideway andusaid groove being cony structed and arranged to control the looseness Y of'said carriage in a radial plane relative to the work, a track 'secured on said face of the main ring having guiding surfaces disposed in radial ,planes relative tothe work, said tool carriage having a bifurcated end on the upstanding leg thereof riding on said track and engageable with said guiding surfaces to control the looseness of said carriage in an axial direction relative to the work without effecting the looseness of said carriage in a radial plane relative tothe work, and tool-carrying jaws on said upstandlng leg of the'carriage between said gib and said track.

V9. In a' rotary tool lathe a rotatable lathe ring "accommodating work therethrough, a carriage slide mounted on a base`of said ring, said slide having pontoons projecting from the back face thereof in spaced opposed relation along the length thereof to hold the slide in spaced relation from the face of the ring and to provide `spaces accommodating passage of chips, a track mountedon said ring in spaced parallel relation from the side, an L-shaped tool carriage having a base leg with a groove along the length thereof receiving said slide and an upstanding leg with a bifurcated end straddling said track, said base leg of the carriage having a screw rod receiving bore therein in spaced parallel relation beneath said groove, a` nutsecuredzin said bore. and a feed screw extending into said bore in threaded relation with said nut for moving said tool carriage on said way and said track.

10. In a rotary tool lathe a slide for the tool carriage thereof comprising an elongated metal bar having a front face with a dove-tailed grooved slot along the length thereof, a back face with pontoons proJecting therefrom at spaced intervals along the length thereof and tapered side walls converging toward the back face, said pontoons having apertures therethrough communicating with the bottom of the slot and countersunk adjacent the bottom of the slot to accommodate screw heads, and a cover plate in said slot covering the apertures therein and providing a flush front face on the slide.

11. In a rotary tool lathe a rotatable main ring member, a tool carriage slide on a face of the `main ring member in spaced relation outwardly from said face, an L-shaped tool carriage having a base leg receiving said slide, a wear strip between one edge wall of the slide and said base leg of the carriage, means for regulating the level of said wear strip, opposed wear strips between the other edge of the slide and said base leg of the carriage having tapered surfaces. devices carried by the base leg of the carriage for sliding said wear strips toward and away from each other for maintaining snug sliding relationship between the base leg of the carriage and said slide, said carriage having an upstanding leg with a bifurcated end, a track on said main ring receiving the bifurcated end in sliding straddling relation thereon, and clamping screws cooperating with the bifurcated end to draw the same into good sliding contact with the track.

12. In a rotary tool lathe, a rotating main lathe ring, a tool carriage slide carried by a face yof said main ring in spaced relationship therefrom to accommodate passage of chips between the slide and the face of the main ring, a tool carriage having a slot in the back face thereof receiving said slide, a wear plate in the bottom of said slot, a bushing strip between an end wall of the slide and a side Wall oi the slot, tapered plugs carried by the carriage acting on said bushing strip to regulate the level thereof. said carriage having a, rod-receiving recess therein, a nut removably mounted in said recess, and a screw rod carried by said ring projecting into said recess and threaded intosaid nut for sliding the carriage on the slide whereby said plug can maintain proper relationship of the slide and the screw rod.

13. In a machine tool, a tool carriage support, a tool carriage slide mounted on a face of said tool carriage support, a tool carriage having a longitudinal slot substantially greater in width than said slide and receiving said slide therein, a bushing between an edge of said slide and said slot and arranged to determine the transverse position of saidy slide in said slot, means in said carriage for adjusting the transverse position of said bushing in said slot, opposed Vwedge strips between the other edge of the slide and said slot, and means on said carriage for actuating said wedge strips to maintain the carriage in snug sliding relationship on said slide.

14. A rotary tool lathe including a main ring having an aperture accommodating work therethrough, a tool Carriage slide on said main ring, a tool carriage track on said main ring, an L- shaped tool carriage having a base leg with a slot therein receiving said slide and an opstanding leg with an end portion receiving said track, said slide and slot being constructed and arl ranged tov control looseness of said carriage relative to the main ring in a radial plane, said track and said end portion being constructed and arranged to control looseness of said carriage relative to the main ring in an axial direction, means for maintaining the base leg of the carriage in snug sliding relationship with said slide, and means for maintaining the bifurcated end of said carriage in snug sliding relationship with said track.

15. In a machine tool, a tool carriage support, a tool carriage way mounted on the face of said tool carriage support in spaced relation therefrom to accommodate passage of chips, a tool carriage having a d ove-tailed slot substantially wider than said slide receiving said slide therein, a level-adjusting strip between one edge of the slide and said slot to position said slide transversely Within said slot, a wear take-up strip between the other edge of the yslide and saidslot, and adjusting devices for said strips to maintain the tool carriage at a desired transverse position in said slot and under desired clearance relationship relative to said slide.

16. In a rotary tool lathe, a ring housing, a bearing ring removably carried by said housing, a main lathe ring having a hub rotatably seated in said bearing ring, said bearing ring providing a radial bearing for said main lathe ring along two spaced localized arcuate segments and providing opposed thrust bearings around the full 360 of said lathe ring, means for introducing lubricant between the hub and the bearing ring to lubricate said localized radial bearing segments and to ilow around the hub for lubricating the thrust bearings completely around the hub.

17. A rotary tool lathe comprising an upstanding ring housing having an open front face and a centrally apertured back wall, a main bearing ring bolted to said back Wall and extending into the aperture thereof, a main lathe ring closing the open front face of said housing and having a hub projecting through said main bearing ring, a thrust ring slidably mounted on said hub acting on said bearing ring, said thrust ring and said back wall of the housing around the aperture having close running clearance relationship, and said bearing ring having an oil groove therein adjacent the gap between the back Wall of the housing and the thrust ring for draining lubricant away from the gap.

18. In a rotary tool lathe, an upstanding ring housing, an oil reservoir in the bottom of said housing, a main bearing ring carried by said housing, a main lathe ring in said housing having a hub rotatably supported in said main bearing ring, a ring gear on said main lathe ring in said housing, a gear meshed with said main ring gear for driving the lathe ring, a pump receiving lubricant from said oil reservoir, piping conveying lubricant, under pressure from said pump to said main bearing ring and to said ring gear and driving gear, and said main lathe ring having troughs therein returning oil to said oil reservoir for recirculation.

19K In a rotary tool lathe, a main ring housing having an open front face, an apertured back wall, and symmetrical laterally projecting wall portions, casings carried by said laterally projecting wall portions, a main lathe ring in said ring housing closing the open face thereof, mechanism ln one of said casings for driving said main lathe ring, mechanism in the other of said casings for lubricating said main lathe ring, and tool carriages slidably mounted on the face of said main lathe ring.

20. In a rotary tool lathe, a bed having elongated longitudinal tracks, a carriage slidably mounted on said tracks, a main housing slidably mounted on said carriage for transverse movement across said bed, said main housing having a central ring portion and laterally projecting casing portions, a platform carried by one of said laterally projecting casing portions, stairs depending from opposite ends of said platform, a stanchion slidably mounted on said bed, a platform carried by said stanchion, and a stair depending from said stanchion platform.

21. In a rotary tool lathe, a bed, a carriage slidable on said bed, a housing slidable on said carriage, said housing having a central ring portion with an open front face and a centrally apertured back wall, a bearing ring carried by said back wall extending into said; aperture, a main lathe ring closing the front face of said ring housing and having a hub supported by said bearing ring, seals on the front of the ring housing and front of the lathe ring, additional seals on the back wall of the housing and on said hub of the lathe ring, and means for introducing lubricant into said bearing ring in said housing for facilitating rotation of the main lathe ring.

LLOYD HORNBOSTEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,899,010 Brittain Feb. 28, 1933 1,020,552 Henry Mar. 19, 1912 1,557,524 Hanson Oct. 13, 1925 2,349,597 Nenninger May 23, 1944 646,078 Moll Mar. 27, 1900 847,426 Moll Mar. 19, 1907 790,519 Moll et al May 23, 1905 1,713,892 Dorin May 21, 1929 520,918 Flather June 5, 1894 1,248,079 Clifton Nov. 27, 1917 1,340,811 Ballman May 18, 1920 898,289 Voorhies Sept. 8, 1908 2,321,741 Flowers June 15, 1943 1,859,989 Schlegelmilch May 24, 1932 FOREIGN PATENTS Number Country Date 12,810 Austria Aug. 10, 1903 144,363 Switzerland Dec. 31, 1930 

